PubMed · 5270266
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G L Manning, R M Browne. 1970-02-17. Dentinoma.. https://doi.org/10.1038/sj.bdj.4802444
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An investigation of the adaptation of dentine to temperature variation was conducted with the aid of digital moiré interferometry and thermomechanical analysis. The moiré interferometric patterns provided direct evidence of two major phases of thermally involved deformation in dentine. An initial phase of expansion was followed by contraction at higher temperatures. Significant gradients in thermal strain and the coefficient of thermal expansion were identified. Close agreement was found between the response of dentine to thermal changes as observed by moiré interferometry and that detected by thermomechanical analysis. This study highlights the biological adaptation of dentine to thermal variations.
OBJECTIVE: The aim of this study was to increase the rate of removal of dentine tissue by a 213-nm laser through the introduction of an Er:YAG assisting laser. BACKGROUND DATA: The rate of dentine removal is increased by using a CO2 laser to assist a XeCl excimer laser. METHODS: Extracted human teeth were sliced parallel to the crown and exposed to 213-nm laser and Er:YAG laser beams that were spatially and temporally aligned. The 213-nm laser radiation was generated using a Q-switched Nd:YAG (5 nsec, 10 Hz) and three nonlinear crystals. The Er:YAG laser was free running with a pulse duration of 100 microsec and a pulse repetition rate of 10 Hz. A fluence range of 5-18.6 J/cm2 (213 nm) and 0.6-1.3 J/cm2 (Er:YAG) was used. Axial ablation rates were measured for different pulse energies and pulse overlaps. RESULTS: The ablation rate of dentine increased in most cases by a factor of two. The highest ablation rate achieved was 18.3 microm/pulse +/- 2.51, which is more than twice the highest ablation rate previously published using a 213-nm laser. Changes in the pulse superpositions that were investigated did not present a significant change in the ablation rate. CONCLUSIONS: The Er:YAG laser can be used to increase the removal rate of dentine by a short-pulse ultraviolet (UV) laser.
A case of clear-cell odontogenic tumor with unusual histological features is presented. A 61-year-old Japanese man was admitted because of swelling of the left premolar-molar region of the mandible. Radiological examination revealed a multilocular radiolucency with irregular margins. Histological examination of the resected specimen showed infiltrative proliferation of both clear and eosinophilic cells into the adjacent soft tissue without encapsulation, suggesting the malignant potential of the tumor. The tumor cells sporadically formed cystic lesions. In addition, several tumor cell nests showed duct-like characteristics, and many eosinophilic dentin-like structures were attached to the tumor cell nests, suggesting the potential for epithelial-mesenchymal induction. Histochemically, the clear tumor cells possessed cytoplasmic glycogen granules. Both clear and eosinophilic tumor cells showed positive immunoreactivities for cytokeratin 19, epithelial membrane antigen and filaggrin, indicating an odontogenic epithelial origin.